Notostomum cyclostomum (Hirudinida: Piscicolidae) parasitic on a flathead flounder, Hippoglossoides dubius (Pleuronectidae), in the southern Sea of Japan off western JapanNotostomum cyclostomum (Hirudinida: Piscicolidae) parasitic on a flathead flounder, Hippoglossoides dubius (Pleuronectidae), in the southern Sea of Japan off western JapanAA11381320

A specimen of the piscicolid leech Notostomum cyclostomum Johansson, 1898 was collected from the eyed body surface of a flathead flounder, Hippoglossoides dubius Schmidt, 1904, caught at 232 m deep in the southern Sea of Japan west off the Oki Islands, Shimane Prefecture, western Japan. This represents the first Japanese record for fish infestation by N. cyclostomum. Hippoglossoides dubius is a new host of N. cyclostomum.